Just an observation. It would seem that the merge vertices function is automatic in version 2.91. When I tried to follow along and do the steps I found that it automatically made the 4 verts just one. Also in the vertex menu, there is no merge, and if you F3 and search merge there is nothing.
‘F3’ Search is context related. So it depends in which mode you are.
Are you in Object or in Edit mode …
I don’t thing merging vertices in 2.91. Just started a new project to check it. Though there is automerge option, which is easy to miss here, which you might have turned on:
Plus, now the shortcut for merging verts is m, not alt+m as it used to be.
Thank you for reply. I see the option now that you mention, however it isn’t selected. Maybe it was selected then ill check it out later. thank you though because that is important knowledge!
Thank you FedPete, now I know two places to find that option. I appreciate you all helping out the newbie!
I didn’t know about the one of bOBaN neither!
But I expect his version is used/needed when the MIRROR option is active.
But there are many solutions to a problem. Ask when needed.
Blender is massive in (hidden) options and/or shortcuts.
Have fun!